GBA Logo horizontal Facebook LinkedIn Email Pinterest Twitter Instagram YouTube Icon Navigation Search Icon Main Search Icon Video Play Icon Audio Play Icon Headphones Icon Plus Icon Minus Icon Check Icon Print Icon Picture icon Single Arrow Icon Double Arrow Icon Hamburger Icon TV Icon Close Icon Sorted Hamburger/Search Icon

Community and Q&A

Shed roof insulation

user-7764336 | Posted in Energy Efficiency and Durability on

Hey – I think I’m on the right track here but just need some confirmation before I go down the wrong path.  So the previous owner added an addition on the back of the house with a shed roof.  This caused serious hot/cold since it was done with open soffits and it just ran right up the side of the house.  I am trying to tighten up the home as I go.  I eventually want to have a continuous layer of 2″ rigid foam on the exterior of the house – we live in Zone 4A and I believe I remember hearing on a BS+Beer show 2″ of rigid foam is enough to keep the dew point outside of the wall assembly on almost any climate zone.

Ok – so I had a roof done about 1-2 years ago and had the contractor put a cor-a-vent like system to allow the roof sheathing to channel air.  I then installed polyiso baffles to channel the air from the soffit to the roof vent.  It gets a little tricky because there is a bulkhead/soffit where the original house and addition meet which has HVAC running through it.  So even if I blocked off the exterior soffit, the sheathing behind the shed roof would still heat up to the temperature of the shed roof “attic” and channel through that interior soffit/bulk head.  I basically blocked off all I could with 2″ rigid foam and then ran 2″ rigid foam up the sheathing (the green lines indicate where I put rigid foam).  Next I am going to fill the joist bays with mineral wool.

I am just looking for some feedback/confirmation that I am not going to cause some unforeseen issues with dew point/amount of foam.

Any advice is helpful – thanks in advance!

GBA Prime

Join the leading community of building science experts

Become a GBA Prime member and get instant access to the latest developments in green building, research, and reports from the field.

Replies

Log in or create an account to post an answer.

Community

Recent Questions and Replies

  • |
  • |
  • |
  • |